Traction network and method for operating a traction network of an electrically-driven transportation vehicle in the event of a short circuit

Abstract

A method for operating a traction power supply system of an electrically-driven transportation vehicle in response to a short circuit, wherein the traction power supply system includes a voltage source and at least two electric drive units connected to the voltage source via respective electrical distribution paths, and wherein at least one electrical isolating element for selective isolation of the voltage source is arranged in the distribution path of each drive unit, wherein, in response to a short circuit in the traction power supply system being detected, the method includes detecting in which distribution path and/or in which drive unit the short circuit is present; operating the traction power supply system in a ready-to-drive state, wherein only that drive unit in which or in the distribution path of which the short circuit is present is isolated from the voltage source.

The invention claimed is: 
     
       1. A traction power supply system for an electrically-driven transportation vehicle powered by voltage, the system comprising:
 a voltage source for powering the electrically-driven transportation vehicle; 
 at least two electrical drive units connected to the voltage source via respective electrical distribution paths; 
 at least one electrical isolating element in each of the electrical distribution paths for selective isolation of the respective electrical drive unit and the respective electrical distribution path from the voltage source; and 
 a controller configured to detect in which electrical distribution path and/or in which electrical drive unit a short circuit is present based on detection of current flow between the at least two electrical distribution paths and, in response to the detection of the current flow, electrically precharging at least one electrical drive unit component, measuring voltages in the at least two electrical distribution paths, and determining a voltage level of a corresponding capacitance in the respective electrical distribution path to determine the electrical distribution path and/or the electrical drive unit having the short circuit, wherein, after the short circuit detection, the controller controls the traction power supply system to be operated in a ready-to-drive state in which the voltage source is isolated from only the electrical drive unit or the electrical distribution path determined to have the short circuit. 
 
     
     
       2. The system of  claim 1 , wherein, in response to decreasing the current flow from a first electrical distribution path to a second electrical distribution path of the at least two electrical distribution paths, it is detected whether the short circuit is present in the second electrical distribution path or the electrical drive unit connected thereto the second electrical distribution path. 
     
     
       3. The system of  claim 1 , wherein the electrical isolating elements in the electrical distribution paths initially remain in a non-isolating state when the short circuit is detected. 
     
     
       4. The system of  claim 3 , wherein at least one of the electrical isolating elements is set to an isolating state only when a predetermined minimum period has elapsed and/or the electrical distribution path having the short circuit and/or the electrical drive unit having the short circuit is detected. 
     
     
       5. The system of  claim 4 , wherein the electrical isolating elements have a predetermined short-circuit strength. 
     
     
       6. The system of  claim 1 , wherein, in response to the electrical precharging for one of the electrical drive units satisfying a predetermined fault criterion, it is detected that the precharged electrical drive unit and/or the electrical distribution path thereof has the short circuit. 
     
     
       7. The system of  claim 1 , wherein, in response to the short circuit detection, the electrical isolating elements are initially set to an isolating state and only the electrical isolating element belonging to a short-circuit-free electrical distribution path is set back to a non-isolating state. 
     
     
       8. The system of  claim 7 , wherein, in response to detection of a current decreasing to a predetermined minimum degree, the short circuit is determined to be present in that electrical distribution path and/or the electrical drive unit connected thereto that has the electrical isolating element; and/or
 wherein, in response to detection of the current not decreasing to a predetermined minimum degree, the short circuit is determined to be present in the electrical distribution path and/or the electrical drive unit connected thereto that does not have the electrical isolating element. 
 
     
     
       9. The system of  claim 1 , wherein: one of the electrical isolating elements is set to an isolating state; and detection of the electrical distribution path having the short circuit and/or the electrical drive unit having the short circuit is determined based on any subsequent change in current within the traction power supply system. 
     
     
       10. A method for operating a traction power supply system of an electrically-driven transportation vehicle powered by voltage, wherein the traction power supply system includes a voltage source for powering the electrically-driven transportation vehicle and at least two electric drive units connected to the voltage source via respective electrical distribution paths, and wherein at least one electrical isolating element is provided in each of the electrical distribution paths for selective isolation of the electrical drive unit and the respective electrical distribution path from the voltage source, the method comprising: in which electrical distribution path and/or in which electrical drive unit a short circuit is present based on detection of current flow between the at least two electrical distribution paths and, in response to the detection of the current flow, electrically precharging at least one electrical drive unit component, measuring voltages in the at least two electrical distribution paths, and determining a voltage level of a corresponding capacitance of the respective electrical distribution path to determine the electrical distribution path and/or the electrical drive unit having the short circuit; and in response to the short circuit detection, controlling operation of the traction power supply system to be in a ready-to-drive state in which the voltage source is isolated from only the electrical drive unit or the electrical distribution path determined to have the short circuit. 
     
     
       11. The method of  claim 10  wherein, in response to the current flow from a first electrical distribution path to a second electrical distribution path decreasing, it is detected that the short circuit is present in the second electrical distribution path or the electrical drive unit connected thereto the second electrical distribution path. 
     
     
       12. The method of  claim 10 , wherein the electrical isolating elements in the electrical distribution paths initially remain in a non-isolating state when the short circuit is detected. 
     
     
       13. The method of  claim 12 , wherein at least one of the electrical isolating elements is set to an isolating state only when a predetermined minimum period has elapsed and/or the electrical distribution path having the short circuit and/or the electrical drive unit having the short circuit is detected. 
     
     
       14. The method of  claim 13 , wherein the electrical isolating elements have a predetermined short-circuit strength. 
     
     
       15. The method of  claim 10 , wherein, in response to the electrical precharging for one of the electrical drive units satisfying a predetermined fault criterion, it is detected that the precharged electrical drive unit and/or the electrical distribution path thereof has the short circuit. 
     
     
       16. The method of  claim 10 , wherein, in response to the short-circuit detection, the electrical isolating elements are initially set to an isolating state and only that electrical isolating element belonging to a short-circuit-free electrical distribution path is set back to a non-isolating state. 
     
     
       17. The method of  claim 16 ,
 wherein, in response to detection of a current decreasing to a predetermined minimum degree, the short circuit is determined to be the short circuit is present in that electrical distribution path and/or the electrical drive unit connected thereto that has the electrical isolating element; and/or 
 wherein, in response to detection of a current not decreasing to a predetermined minimum degree, the short circuit is determined to be the short circuit is present in that electrical distribution path and/or the electrical drive unit connected thereto that does not have the isolating element. 
 
     
     
       18. The method of  claim 10 , wherein: one of the electrical isolating elements is set to an isolating state; and detection of the electrical distribution path having the short circuit and/or the electrical drive unit having the short circuit is determined based on any subsequent change in current within the traction power supply system.